The total monthly bill of the gym = $53
The cost of membership of a month = $25
Let 'n' be extra the number of hours Bella worked on.
The cost for working on extra hours = $4
So, we have to determine the equation, Bella worked out after hours.
We will determine the equation by:
(Monthly cost of membership) + ( cost for extra hours number of hours extra worked on ) = Total monthly bill received
So, we get
$25+4n = $53 is the required equation.
Therefore, $25+4n = $53 equation can be used to determine how many times Bella worked out after hours.
In order to be differentiable everywhere, must first be continuous everywhere, which means the limits from either side as
must be the same and equal to
. By definition,
, and
so we need to have .
For to be differentiable at
, the derivative needs to be continuous at
, i.e.
We then need to have
Then